Bottom residues resulting from the synthesis of isoprene and isoamylene by dehydrogenation of isopentane

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 May to XY July 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: studiy performed according to OECD 301 B guideline and GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Absorbent N grade A

IUPAC Name:

Absorbent N grade A

Details on test material:

- Name of test material (as cited in study report): Absorbent N grade A
- Substance type: UVCB
- Physical state: Brown liquid
- Stability under test conditions: months
- Storage condition of test material: room temperature, in the dark

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Prior to use a sample of activated sludge from the sewage plant at Taunusstein-Bleidenstadt was washed twice with mineral nutrient solution of the CO2-Evolution-Test to eliminate organic components and carbonates from the sludge. After resolution with mineral nutrient medium the sludge was aerated by means of compressed humidified air for about four hours. Before use as inoculum for the CO2-Evolution-Test the sludge was homogenised in a "Waring Blender" at low speed for 2 minutes and then filtered through a cotton filter previously carefully rinsed with deionised water. The filtrate was used as inoculum (1% of the final volume of the test solution) on the same day of preparation.

Duration of test (contact time):

ca. 28 d

Initial test substance concentration

Initial conc.:

ca. 50.5 - 51.5 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: as mentioned in the guideline
- Additional substrate: none
- Solubilising agent: none
- Test temperature: Values were in the range of 20.6 to 23.7 °C (mean 21.8°C)
- pH: data not available
- pH adjusted: no
- Aeration of dilution water: the aeration rate of the test system was controlled at 4 L/h
- Continuous darkness: data not available

TEST SYSTEM
- Culturing apparatus: ≈5-litre amber carboys served as test vessels. They were closed with stoppers with tubing for gas inlet and outlet (gas exit line)
- Number of culture flasks/concentration: two vessel with the test item, one vessel with sodiumbenzoate (control item), one toxicity control
- Method used to create aerobic conditions: aeration

SAMPLING
- Sampling frequency: Titrations were performed at t3d, t5d, t10d, t14d, t20d, t28d, and t29d
- Sample storage before analysis: data not available

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: no
- Toxicity control: yes

STATISTICAL METHODS: not applicable

Reference substance

Reference substance:

benzoic acid, sodium salt

Remarks:

20 mg TOC/L

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

5

Sampling time:

28 d

Remarks on result:

other: mean value

Details on results:

Calculated from the organic carbon content of the test item and the measured CO2 generation, 0.5 % of the theoretical CO2 (ThCO2) has been generated by the test item within 28d of test period in the first culture with 51.5 mg of test item. 10.4 % of the theoretical CO2 (ThCO2) has been generated by the test item within 28d in the second culture with 50.5 mg of test item. The calculated mean degradation value of the test item was 5 %.

BOD5 / COD results

Results with reference substance:

The control item sodium benzoate was degraded 79 %, the "10-days-window" being met within 7 days (71 %).

Any other information on results incl. tables

Table 1: Results of Testing Biodegradability according to OECD 301 B – 1^stTest Solution, Test Item

Date	Time [d]	1^stTest Solution with»13 mg C/L		% TCO2 (= % Biodegradation)^3)
		mg CO2generated in the test solution, cumulative
03-Jun-2011 07-Jun-2011 10-Jun-2011 14-Jun-2011 21-Jun-2011 28-Jun-2011 29-Jun-2011	3 7 10 14 21 28 29	0.00 0.00 0.00 0.12 0.34 0.34 0.81		0.0 0.0 0.0 0.1 0.2   0.2^4)   0.5^5)

¹⁾TOC:         Total Organic Carbon

²⁾ThCO₂:       Theoretical amount of CO₂that can be generated by the test item

³⁾% TCO₂:     Percentage of total CO₂the test item has generated in relation to the ThCO₂

⁴⁾                  The test solution was stopped by the addition of 1 mL conc. HCl;

⁵⁾                  The difference between this titration and that before is due to the liberation of CO₂after acidification of the test soluti

Table 2: Results of Testing Biodegradability according to OECD 301 B - 2^ndTest Solution, Test Item                     

Date	Time [d]	2^ndTest Solution with»13 mg C/L		% TCO2 (= % Biodegradation)^3)
		mg CO2generated in the test solution, cumulative
03-Jun-2011 07-Jun-2011 10-Jun-2011 14-Jun-2011 21-Jun-2011 28-Jun-2011 29-Jun-2011	3 7 10 14 21 28 29	0.30 2.25 3.98 7.25 11.28 15.23 17.04		0.2 1.4 2.4 4.4 6.9   9.3^4)  10.4^5)

  

¹⁾TOC:         Total Organic Carbon

²⁾ThCO₂:       Theoretical amount of CO₂that can be generated by the test item

³⁾% TCO₂:     Percentage of total CO₂the test item has generated in relation to the ThCO₂

⁴⁾                  The test solution was stopped by the addition of 1 mL conc. HCl;

⁵⁾                  The difference between this titration and that before is due to the liberation of CO₂after acidification of the test solution.

Table 3: Results of Testing Biodegradability according to OECD 301 B – 3^rdTest Solution, Sodium Benzoate

Date	Time [d]	3^rdTest Solution with»22 mg C/L Sodium Bezoate		% TCO2 (= % Biodegradation)^3)
		mg CO2generated in the test solution, cumulative
03-Jun-2011 07-Jun-2011 10-Jun-2011 14-Jun-2011 21-Jun-2011 28-Jun-2011 29-Jun-2011	3 7 10 14 21 28 29	135.63 182.21 190.62 198.15 202.90 203.80 203.80		53 71 74 77 79   79^4)   79^5)

  

¹⁾TOC:         Total Organic Carbon

²⁾ThCO₂:       Theoretical amount of CO₂that can be generated by the test item

³⁾% TCO₂:     Percentage of total CO₂the test item has generated in relation to the ThCO₂

⁴⁾                  The test solution was stopped by the addition of 1 mL conc. HCl;

⁵⁾                  The difference between this titration and that before is due to the liberation of CO₂after acidification of the test solution.

Table 4: Results of Testing Biodegradability according to OECD 301 B - 4^thTest Solution, Toxicity Contro

Date	Time [d]	4^thTest Solution with ≈20 mgC/L Sodium Benzoate +»12 mg C/L TS		% TCO2 (= % Biodegradation)^3)
		mg CO2generated in the test solution, cumulative
03-Jun-2011 07-Jun-2011 10-Jun-2011 14-Jun-2011 21-Jun-2011 28-Jun-2011 29-Jun-2011	3 7 10 14 21 28 29	121.41 164.79 177.80 192.16 216.00 217.89 221.72		29 40 43 46 52   52^4)   53^5)

 

¹⁾TOC:         Total Organic Carbon

²⁾ThCO₂:       Theoretical amount of CO₂that can be generated by the test item

³⁾% TCO₂:     Percentage of total CO₂the test item has generated in relation to the ThCO₂

⁴⁾                  The test solution was stopped by the addition of 1 mL conc. HCl;

⁵⁾                  The difference between this titration and that before is due to the liberation of CO₂after acidification of the test solution.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: not readily biodegradable

Conclusions:

the test item may be regarded as “not readily biodegradable".

Executive summary:

“Absorbent N grade A“was tested for biodegradability according to 'CO₂-Evolution-Test' (OECD Guideline 301B). Calculated from the organic carbon content of the test item and the measured CO₂generation, 0.5 % of the theoretical CO₂(ThCO₂) has been generated by the test item within 28d of test period in the first culture with 51.5 mg of test item. 10.4 % of the theoretical CO₂(ThCO₂) has been generated by the test item within 28d in the second culture with 50.5 mg of test item. The calculated mean degradation value of the test item was 5 %. Thus, the test item may be regarded as “not readily biodegra­dable". The control item sodium benzoate was degraded 79 %, the "10-days-window" being met within 7 days (71 %). The total CO₂-evolution of the Blank was 93 mg CO₂. Thus the test is regarded to be valid. The results obtained with the toxicity control indicate that there was no toxicity of the test item towards microorganisms at the concentration used within the test.